The Long Range Goals of this project are to understand the origin and evolution of transposable elements in insect genomes, to apply gene transfer technology to the molecular genetic investigation of insect vectors of human diseases such as malaria, leishmaniasis and trypanosomiasis, and to used gene transfer technology to control the incidence and spread of these diseases. Transposable elements are genetic elements that can influence the structure of genomes and the expression of genes in a variety of ways. They are also of profound technical significance because they can be harnessed to serve as gene vectors, facilitating the molecular genetic analysis of biological systems. Gene vectors are currently unavailable for insects outside the genus Drosophila and are critically needed for the molecular genetic analysis of vector/parasite interactions. Preliminary Data described in this proposal indicate that the hobo element from Drosophilia melanogaster is capable of functioning in other insect species and that related elements exist in these insects. These data are consistent with recent evidence indicating that hobo is member of a widespread family of elements including the plant transposable elements Ac and Tam3, and the hypothesis that hobo arose in Drosophila as a result of horizontal (interspecific) transfer from a non-drosophilid species. The Specific Aims are to 1) assess the mobility of hobo elments in non-drosophilid insects, 2) identify and isolate hobo-like DNA sequences from non-drosophilid insects, 3) identify and isolate factors from non-drosophilids with hobo-transposase-like activity, 4) construct and test gene vectors for non-drosophilid insects. This Project is Related to Human Health because it will lead to an understanding of the biology of insect vectors of human diseases and eventually to new strategies for the control of the incidence and spread of these diseases. The Experimental Design relies on the implementation of in vivo transient expression and transposable element mobility assays to assess element mobility and to identify new elements. Methods will include isolation of transposable elements from genomic libraries using homologous DNA probes and degenerate oligonucleotides, the isolation of transposable element binding proteins using gel retardation assays and affinity gel purification methods and the assessment of element and vector mobility by microinjection of insect embryos.